Fiber recovery unit for knitting machine



July 25, 1961 s, WHEELOCK 2,993,351

FIBER RECOVERY UNIT FOR KNITTING MACHINE Filed Nov. 12, 1959 This invention relates generally to the production of pile fabrics and, more particularly, to improvements in the machines which are employed in knitting such fabrics.

It is well known that, in the operation of coventional sliver knitting machines, a significant percentage of the processed fibers is lost as the fibrous mass is transferred from the carding head to the knitting needles.

The most important object of the present invention is to provide a fiber recovery unit adapted for use with otherwise conventional sliver knitting machines.

A further important object is the provision of a fiber recovery unit which includes means for returning recovered fibers directly back to the carding head of a knitting machine with the result that the need for reprocessing the recovered fibers is eliminated.

Another object of the present invention is to present a process improvement which involves the steps of collecting and redepositing free fibers continuously during the knitting process.

With these and other objects in view, a fiber recovery unit is disclosed herein which includes an exhaust stack having an inlet located adjacent a knitting machine and a fiber recovery device which has means within the stack for collecting the recovered fibers as well as conveyor means leading from the stack to a carding head for returning the collected fibers directly into the process.

Other objectives will become apparent in the following specification wherein reference is made to the accompanying drawing in which the exhaust stack and recovery unit of the present invention have been shown in combination with a sliver knitting machine.

The sliver knitting machine which has been chosen for purposes of illustration is of the type which has been disclosed by Brandt in US. Patent No. 2,710,525. The carding head, which has been shown only partially, includes a lickerin cylinder 10, a main cylinder 12, an intermediate cylinder 14 and a feed cylinder 16. There are preferably a number of such carding heads radially spaced around a rotatable needle cylinder 18. Each of the heads includes a frame on which a motor 20 is mounted as a prime mover for the various cylinders and for the needle cylinder. A plurality of needles 19 on cylinder 18 penetrate a proper depth into the fibrous mass on feed cylinder 16 during the knitting operation. Further details as to the formation of the pile fabric have been omitted from this specification since the actual construction and operation of any particular knitting machine are not within the scope of the present invention.

Above the cylinder 18, there is located an exhaust stack 22 having a fan 24. The free fibers which are normally lost at the knitting location are picked up by the air moving into stack 22. One of the card heads surrounding the cylinder 18 has associated therewith a pair of rolls 26, 28 which are driven by the corresponding motor 20, all as shown in the drawing. The other card heads (not shown) may be arranged, for example, in the manner disclosed by Brandt. A perforated or foraminous continuous belt 30 is trained over roll 26 and rolls 32, 34, the latter being rotatably mounted in openings provided therefor in the side walls of stack 22. The belt thus entirely traverses stack 22 as it travels therethrough. Belt 30 may be made of metal or a suitable 2,993,351 Patented July 25, 1961 synthetic material. At the point where belt 30 leaves stack 32, there is provided a tray or shell 36 which extends to a conveyor belt 38 that is trained over the driven roll 28 and a roll 40.

In operation, stack 22 and fan 24 function to evacuate free fibers from the knitting location. The evacuated fibers may comprise as high as 35% of the total fibers processed. Within the stack, these free fibers are collected against the moving belt 30 and held thereon by suction. Belt 30 thus acts as a fiber collection device. The vacuum is maintained until such time as the belt has passed beyond roll 32. At this point, the fibers are deposited on conveyor belt 38 and eventually on the main cylinder 12.

It is apparent that fan 24 must have sufiicient capacity to maintain a vacuum in stack 22 if the unit is to operate effectively. In this respect, it is noted that even though the belt becomes substantially matted with fibers as it traverses the stack there will always be a continuous flow in the area of the belt which is adjacent to roll 34. As belt 30 passes over tray 36, the free fibers are still held by the vacuum in stack 22. Maintenance of this vacuum is enhanced by the use of solid rolls 32, 34 and by the provision of suitable sealing strips 42 which extend through the length of rolls 32, 34. The matted fibers preclude the entrance of air through the passage between belt 30 and tray 36.

The improved process includes, in addition to the conventional knitting steps, the evacuation of free fibers from a knitting location, the collection of evacuated fibers, and the immediate return of collected fibers at a suitable stage in the carding operation. When the evacuation step alone is followed, the fibers are either blown to waste or collected and completely reprocessed. By incorporating the immediate collection and return steps disclosed herein, the time and expense of reprocessing are avoided.

It is apparent that many changes and modifications may be made in the disclosed fiber recovery process and apparatus without departing from the spirit of the present invention which is therefore intended to be limited only by the scope of the appended claims.

I claim:

1. In a sliver knitting machine including a needle cylinder and at least one carding head feeding to the needle cylinder at a knitting location: an exhaust stack having an inlet located above the knitting location for the removal of free fibers; and a fiber recovery unit including conveyor means leading from the stack to the carding head and a fiber collection device within the stack, said device being coupled with the conveyor means for the distcharge of collected fibers thereto.

2. The sliver knitting machine of claim 1 wherein said fiber collection device comprises a traveling, foraminous belt traversing said stack and extending at least as far as said conveyor means.

3. The sliver knitting machine of claim 2 wherein is provided a tray beneath said belt and extending from the stack to the conveyor means.

References Cited in the file of this patent UNITED STATES PATENTS 1,141,034 Bazino May 25, 1915 1,752,207 Seifert Mar. 25, 1930 2,045,509 Allred June 23, 1936 2,152,901 Manning Apr. 4, 1939 2,581,069 Bertolet Jan. 1, 1952 2,648,876 Phillips et al. Aug. 18, 1953 2,710,525 Brandt June 14, 1955 FOREIGN PATENTS 195,802 Great Britain Apr. 12, 1923 

